A cluster tool, for example, is a processing system constructed with a plurality of process modules that are arranged around a main transfer chamber so that the modules can each perform the same process or a different process continuously or concurrently, and is typically employed in semiconductor-manufacturing equipment (refer to JP2000-127069A, for example).
In such a cluster-tool type of processing system, each process module has a process module controller configured to control the operation and states of the internal sections of the module and to control the execution of the process. In addition, a transfer mechanism within the main transfer chamber has a transfer module controller configured to control the transfer procedures and the operation of transfer arms. Predetermined single-substrate processing by each process module and substrate transfer by the transfer mechanism are repeated at fixed time cycle and in a fixed transfer pattern, while recipe information, control signals, and the like are communicated between the module controllers and a main controller that undertakes integrated control of the entire system. In particular, when plural process modules or plural sets of process modules perform processes of the same recipe in parallel, productivity of a single-process or a composite-process can be doubled.
Such a processing system as discussed above usually operates continuously for a long period of time to achieve high productivity, and is also flexible enough to perform various kinds of processes depending on process recipes. Between production lots, “conditioning” that stops all intra-system substrate transfer operations and adjust intra-module parameters to predetermined values is performed in each process module for execution of new process recipes, using a considerable long time. Typical examples of such parameters include, for example, the internal temperatures and inner-wall states of the process chamber or vacuum chamber of the process module. The temperature of a susceptor for holding and heating the substrate is particularly important as the internal temperature of the chamber.
However, even in a case where a plurality of process modules or plural sets of process modules perform processes of the same recipe, since the process modules have individual differences, the time necessary for the parameters to reach predetermined values may vary between the process modules. For example, even if the process temperature defined by the recipe is 600° C., there may be a case where the set susceptor temperature is 590° C. in one process module and 610° C. in another process module. In addition, even if the set susceptor temperature is the same between process modules, variation in the sensitivity of temperature sensors provided in respective process modules due to individual difference may cause differences in the timing at which the arrival at the predetermined temperature is judged. In such cases, the time when conditioning is completed will vary between the process modules, and the difference between the maximum value and minimum value of the conditioning-completion time will increase as the number of process modules is increased.
Conventional cluster tools are constructed so that if there is even one process module that has not completed conditioning for a new process recipe, all other process modules stand by and when conditioning of the last process module is completed, all process modules will start to operate at the same time. Under such stand-by state as mentioned above, however, the system itself is in substantially no operation. Conventional systems have therefore admitted of improvement in productivity.